最新研究稱鹽攝入量過(guò)少對(duì)健康有害 食品行業(yè)面臨新難題
????鹽絕對(duì)是大多數(shù)加工食品中不可或缺的一種原料。因此,食品行業(yè)因?yàn)橐豁?xiàng)最新研究結(jié)果而陷入混亂,也就不顯得意外。該研究稱,食物中含鹽過(guò)少可能與含鹽過(guò)多有同樣的危害。 ????但到目前為止,食品行業(yè)一直在小心翼翼地應(yīng)對(duì)這項(xiàng)研究結(jié)論。原因有兩個(gè):首先,因?yàn)槭称分圃焐躺胁磺宄撊绾螌?duì)待《新英格蘭醫(yī)學(xué)期刊》(New England Journal of Medicine)近期公布的這些新數(shù)據(jù);其次,多年以來(lái),食品行業(yè)已經(jīng)形成了一個(gè)紅火的“低鈉”食品市場(chǎng)。任何與鹽有關(guān)的概括陳述,都會(huì)對(duì)該行業(yè)的某個(gè)部分造成損壞。 ????《新英格蘭醫(yī)學(xué)期刊》共發(fā)表了三項(xiàng)研究結(jié)果。其中兩項(xiàng)研究的結(jié)論是,鹽攝入量過(guò)低可能有害。第三項(xiàng)研究基本上符合此前的研究成果,這項(xiàng)研究發(fā)現(xiàn)每天鈉攝入量超過(guò)兩克,便會(huì)增加心血管疾病的風(fēng)險(xiǎn)。兩克是世界衛(wèi)生組織建議的最高攝入量(相當(dāng)于5克鹽,因?yàn)槭雏}中含40%的鈉)。前兩項(xiàng)研究因?yàn)槭褂玫姆椒ǘ獾脚u(píng),但它們卻引起了媒體的興趣——這沒(méi)有什么奇怪的,媒體就是喜歡這種違反直覺(jué)的科學(xué)故事。第三項(xiàng)研究則更為嚴(yán)謹(jǐn),受到的批評(píng)要少得多。 ????這三項(xiàng)研究當(dāng)然都是合理正當(dāng)?shù)摹冀?jīng)過(guò)同行評(píng)議且在著名期刊上發(fā)表。至于研究人員所謂“過(guò)分低的”鹽攝入量目標(biāo)會(huì)影響人體健康,并沒(méi)有具體的科學(xué)依據(jù)。前兩項(xiàng)研究屬于觀察性研究,僅發(fā)現(xiàn)低鈉攝入量與心血管疾病風(fēng)險(xiǎn)存在一種聯(lián)系,但并非因果關(guān)系。需要進(jìn)行更多研究才能確定兩者之間的具體關(guān)系,但上周發(fā)表的三項(xiàng)研究均反對(duì)一項(xiàng)壓倒性的科學(xué)共識(shí)(雖然并非普世共識(shí)):一般而言,我們攝入過(guò)多鹽會(huì)帶來(lái)健康風(fēng)險(xiǎn),尤其是高血壓。 ????研究發(fā)表以后,食品雜貨制造商協(xié)會(huì)(Grocery Manufacturers Association)呼吁就該問(wèn)題進(jìn)行更多研究,這與《新英格蘭醫(yī)學(xué)期刊》本身的觀點(diǎn)基本類似。食品雜貨制造商協(xié)會(huì)非常謹(jǐn)慎,沒(méi)有對(duì)新研究表示特別支持(或質(zhì)疑),鑒于其所處的兩難境地,這種態(tài)度在預(yù)料之中。從食品雜貨制造商協(xié)會(huì)的聲明中便能看出其面臨的難題。這份聲明更像是一段內(nèi)部討論: ????“數(shù)十年來(lái),食品雜貨制造商協(xié)會(huì)的成員一直在調(diào)整食品的成分,希望為消費(fèi)者提供低鈉選擇,幫助消費(fèi)者達(dá)到健康的鈉攝入量水平。為了減少鈉含量并滿足消費(fèi)者的口味偏好,我們的行業(yè)對(duì)數(shù)千種食品的成分進(jìn)行了重新調(diào)整。此外,我們的行業(yè)還開(kāi)發(fā)出各種減少鈉含量、低鈉或不添加鈉的食品,以幫助消費(fèi)者遵從醫(yī)療保健專業(yè)人員的建議?!?/p> |
????Salt is an absolutely essential ingredient in most processed food. So it’s no surprise that the food industry is starting to make a little hay of new research concluding that too little salt in the diet might be as harmful as too much. ????But the industry so far is treading carefully. There are two reasons for that: first, because at this point it’s impossible for food producers to know what to do with this new data, all of it published recently by the New England Journal of Medicine; and second, because over the years, the food industry has created a whole thriving market for “l(fā)ow sodium” products. Any kind of sweeping statement on salt would hurt one part of the industry or another. ????Three studies were published. Two of them concluded that underconsumption of salt might be harmful. A third basically matched the findings of earlier research, showing that cardiovascular risk rises with increases in sodium consumption of over 2 grams per day — the maximum recommended by the World Health Organization (that’s the equivalent of 5 grams of salt, since salt is about 40% of salt). The first two have drawn criticism because of the methodology used, but those are the ones the media picked up on — which is not surprising given that the media love counterintuitive science stories. The third study was far more rigorous and far less assailable. ????All three studies are certainly legitimate — peer reviewed and published in a prestigious journal. And there’s not much science behind how what researchers called “aggressively low” salt targets might affect human health. But the first two were observational and found only an association between such low sodium intake and cardiovascular risk, not a cause-and-effect relationship. More study is surely needed, but none of the research published last week counters what is the overwhelming (though not universal) scientific consensus: that in general we eat too much salt and that it poses health risks, particularly hypertension. ????After the research was published, the Grocery Manufacturers Association called for more study of the question, basically echoing what the New England Journal of Medicine itself said. The GMA was careful not to specifically endorse (or dispute) the new research, which is not surprising given the quandary it presents. The problem can be seen within the GMA’s statement itself. It’s almost an internal dialogue: ????“GMA members have been reformulating products for decades to provide lower sodium options to help consumers achieve healthy sodium intake levels. Our industry has reformulated thousands of products to reduce sodium content and meet consumer taste preferences. The industry has also developed a wide variety of reduced, low or no-added sodium products to help consumers follow recommendations of their health care professionals.” |